The present invention relates generally to agricultural implements, and more specifically to multiple implement hitches which fold between a wide field-working configuration and a narrower transport configuration.
As tractor size and horsepower increase, wider agricultural implements have been introduced to increase productivity. Since the field-working widths of many of the implements are greater than acceptable transport and storage widths, folding frames or hitches have become necessary. Examples of typical folding frame or hitch structure may be found in U.S. Pat. Nos. 3,791,673, 4,214,637 and 4,272,097.
For the most part, prior art folding structures have been relatively bulky and complex. Many have included telescoping or centrally hinged diagonal beams which require accurate alignment and which can bind or buckle under heavy loading, such as when the structures are folded or stopped suddenly while supporting fully loaded grain drills or the like. Some of the prior art structures also require the supported implements to be connected at their innermost ends, either to each other or to the frame or hitch itself, and such connection can limit flexibility and cause uneven planting or tillage in rough terrain. Height variations of the structure, such as result when the wheels supporting the frame or hitch encounter rough field conditions, are commonly transmitted directly to the attached implements.
Another disadvantage of some prior art folding equipment is that the attached implements must be specifically designed or modified for attachment to the structure, and therefore an individual implement cannot be conveniently disconnected and used separately behind a tractor for smaller jobs. Often a farmer having a conventional implement either must extensively modify that implement or, alternatively, buy all new implements for use with a particular folding frame or hitch. Although some prior art structures are available to mount conventional implements, these tend to be quite complex. Those such as exemplified in the aforementioned U.S. Pat. No. 4,272,097 require a pair of running gear which reorient as the structure changes between transport and field-working positions.
It is therefore an object of the present invention to provide an improved hitch for supporting agricultural implements in a side-by-side configuration for use in the field and in a folded configuration for transport.
It is yet another object to provide a hitch which overcomes many of the problems associated with the prior art structures.
It is yet another object to provide a hitch which is simpler in structure, stronger and less expensive to manufacture than at least some of the prior art hitches.
It is a further object of the invention to provide a folding multiple implement hitch which receives an existing implement without extensive modification. It is another object to provide such a hitch which accepts a conventional three-point hitch mounted implement.
It is still another object of the invention to provide a multiple implement hitch having an improved lift arrangement for positively raising and supporting the implements during transport and for providing increased flexibility in the field. It is a further object to provide such a hitch which obviates complicated folding or telescoping members and which utilizes simple wheel structure.
In accordance with the above objects, a two-wheeled trailer hitch is supported for forward movement over the ground by a pair of rearwardly mounted ground-engaging wheels. Outriggers are pivotally mounted at the rear of the hitch for swinging between transversely outwardly extending positions and forwardly extending positions. The outward ends of the outriggers carry connecting structure adapted for connection to the existing three-point hitch structure on the implements. Hydraulically operated lift frames raise and lower the implements between upper transport positions wherein the implements are carried on the respective outriggers, and lower ground-engaging positions. In the lower ground-engaging position, the lift frame permits the individual implements to move independently over rough terrain. To narrow the structure for transport, the implements are raised on their respective outriggers, and the outriggers are pivoted forwardly approximately ninety degrees by a pair of rigid diagonal links connected to a hydraulically actuated slide block. A fore-and-aft cylinder is extended to move the slide block forwardly and pull the outriggers to a position adjacent hitch beams. Brackets located on the hitch beams mate with support rollers adjacent the lift frame as the structure is folded and provide support near the ends of the outriggers during transport. A safety pin locks the slide block in position during transport to prevent unfolding.
The connecting structure permits conventional implements to be quickly and easily attached to or removed from the hitch. The lift frames provide positive lifting action for the implements while permitting flexibility in the field-working position. The hydraulically operated folding structure permits the use of rigid diagonal braces rather than telescoping or folding braces which reduces the cost and complexity of the unit while providing added strength to resist buckling, particularly when fully loaded grain drills or the like are supported on the hitch.
These and other objects, features and advantages of the present invention will become apparent to one skilled in the art from the description below when taken with the drawings.